We purchased a 2010 in Oct. of 2010. From the start, the fuel mileage is discussing. Each time they say "it gets better at 5000 km, then 10,000, km, now up to 30,000m it is poor. It seems as though there is no coast when there is no gas pedal pushed, like other ones I’ve been in. It feels like I’m plowing all the time. Then at 15, 000, the replaced a brake disk, and yada yada.

After taking it across a 5,000 trip it remains way less than stated.
So I found a technical service bulletin on the net. I took it to the service guys whom look like they were caught in the head lights. It mentions some issue with the computer sending messages to the transaxle, thus the "resistance issue" So a few times they "reset it", whatever "It is” and it appeared for a bit to run better. For about 100 km only. We managed 1 time to get 590 km from a tank, and mostly are about 375 km to a tank, highway. That sucks. Any Ideas?

 

Yeah, I got 2 ideas. First, get one of these:


Second, change your driving habits.

You gave us no information. What is the mileage you are getting? Manual or auto? What kind of driving do you do? Heavy foot or granny? City or highway? Hilly or flat? A lot of A/C usage? Tires are correct pressure?

 

Yes, the grammatical errors aside, Thanks for the Dan Webster idea.
I have a 4 cylinder, automatic, 2010 Hyundai Accent. I average 12- 14 liters per 100 km, on the highway, at its best, and have recorded a best of 11 kmh/liter ( just after having the computer reset). By the way, the reset seemed to last about 100 km only.

The issue that I find, is that the car does not seem to coast. It has resistance when not accelerating. KINDA LIKE ITS PLOWING....

Is a master mechanic the best way to go? Are there many reported issues with the computer and trans axel issue?

 

Further

The tires are new, had them all reviewed, pressure is OK, mostly highways that are flat, not a fan of air conditioner usage, and not a lead foot.

 

My guess is its a clutch-pack in the tranny, or a bad seat between the axles and transaxle.

Something else to check would be brakes, just for giggles. Take your car out on a long stretch of road, drive about a mile or so at a constant speed, then try coasting to a stop and pull over. Touch a lugnut on each wheel, if theyre HOT then its brakes, being warm is normal, you should be able to keep your finger on the bolt.